A data warehouse is a centralized repository designed to store, manage, and analyze large volumes of structured and sometimes semi-structured data. It is optimized for querying, reporting, and data analysis rather than transaction processing. Data warehouses aggregate data from multiple sources, including databases, external data feeds, and other information systems, transforming and organizing it for business intelligence and decision-making purposes. Key Characteristics of a Data Warehouse: 1. Subject-Oriented: Organized around key business areas like sales, finance, or customer data. 2. Integrated: Combines data from disparate sources into a consistent format. 3. Non-Volatile: Data is stable and does not frequently change once entered into the warehouse. 4. Time-Variant: Stores historical data, allowing for trend analysis and comparisons over time. Common Use Cases: Generating business intelligence reports. Performing complex queries and data analysis. Supporting decision-making pro...
Data Modeling Data modeling is the process of creating a conceptual representation of data and its relationships within a system or organization. It serves as a blueprint for designing and implementing databases by organizing and structuring data logically. Purpose: Understand the data requirements of a system. Define how data is stored, organized, and retrieved. Identify relationships between different data entities. Types of Data Models: 1. Conceptual Data Model: High-level design for understanding business requirements. Focuses on entities, attributes, and relationships. Tools: Entity-Relationship (ER) diagrams. 2. Logical Data Model: Provides more detail, including attributes, primary keys, and foreign keys. Independent of any specific database technology. 3. Physical Data Model: Details how data is stored in a database, including tables, columns, indexes, and constraints. ---Entity-Relationship (ER) Diagram An ER Diagram is a visual representation of data and its relationship...
computer key board कीबोर्ड- आधुनिक कंप्यूटर कीबोर्ड का इतिहास टाइपराइटर के आविष्कार से प्रत्यक्ष विरासत के साथ शुरू हुआ था । क्रिस्टोफर लैथम शोल्स ने पहले व्यावहारिक आधुनिक टाइपराइटर का पेटेंट कराया था। इसके तुरंत बाद, 1877 में, रेमिंगटन कंपनी ने पहले टाइपराइटर का बड़े पैमाने पर विपणन शुरू किया। तकनीकी विकास की एक श्रृंखला के बाद, टाइपराइटर धीरे-धीरे मानक कंप्यूटर कीबोर्ड में विकसित हुआ था । It is primary input device.used text base. there are different type of key board. Alpha numeric - It is use for Enter no. & text. Punctuation- Use forEnter addionational key (), : ,; Navigation- It use for move to cursor. Special - Perform some special task ( f5, f8). Window- Use for open window like start menu. Function- Use for help. (f2). Numeric- Use for enter numeric no. Modification- used for enter to the capital letter. PC / AT- pc/at introduced by I.B.M. It had 84 key. 101 key board replaced it. 101 key board- Introduced by i.b.m. in ...
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